Gas blast circuit breaker



March 14., 1933. w. UEBERMUTH 1,901,679

GAS BLAST CIRCUIT BREAKER Filed March 8, 1952 Inventor Werner-Uebermuth,

His Attorneg.

Patented Mar. 14,1933

UNITED STATES PATENT OFFICE WERNER 'UEBERMUTH, OF OBERSCHONEWEIDE,GERMANY, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORKGAS BLAST CIRCUIT BREAKER Application filed March 8, 1932, Serial No.

' My invention relates to gas blast circuit brea ers, more particularlyto means for operating a gas blast circuit breaker with a minimumexpenditure of gas energy.

In the operation of gas blast, circuit breakers wherein a common sourceof gas pressure is utilized to effect the gas blast and interruption ofarcing and also mechanical separation of the switch contacts, it hasbeen proposed to use a common valve serving both purposes. Since the arcextinguishing blast is generally effective to interrupt the circuitwithin a very short time, as of the order of a cycle or so ofalternating current, and since the mechanical separation of the contactsto the fully open circuit position involves a much longer time, it willbe apparent that the arc extinguishing blast is continued for a muchlonger time than necessary resulting in appreciable loss of gas energy.The problem may be concisely stated as follows: The are extinguishingblast requires a large volume of gas at high pressure for a short periodof time, whereas the circuit opening operation requires but acomparatively small volume of gas at a lower pressure for a considerablylonger period of t me. Due to the high pressure required for the arcextinguishing blast, a large amount of gas energy is dis- 3 sipated bythe blast after actual interruption of arcing and prior to completion ofthe switch opening movement.

A principal object of my invention is the provision-of an improved gasblast circuit breaker having means arranged to shut oil or discontinuethe gas blast after a brief time and for continuing application of gaspressure to the switch opening mechanism to complete the switch openingoperation.

My invention will be more fully set forth in the following descriptionreferring to the accompanying drawing, and the features of novelty whichcharacterize my invention will be pointed out with particularity in the597,585, and in Germany March 10, 1931.

claims annexed to and forming a part of this specification.

The single figure of the drawing is a partly diagrammatic View, partlyin section, of a gas blast circuit breaker embodying the presentinvention.

The gas blast circuit breaker illustrated by way of example comprises astationary nozzle-like contact 1 and a movable rod contact 2 mounted forlongitudinal, reciprocal movement within an insulating sleeve-likecasing 3 at the upper end of which the contact 1 is mounted. As is wellknown, the operation of this type of switch involves a source of gaspressure, as a reservoir or pressure tank 4, and a main controllingvalve 5 arranged to admit gas under pressure to the casing 3 so that astrong blast is directed across the are and through the nozzle-likecontact 1 when the rod contact 2 is drawn toward open circuit position.

Referring more particularly to the structure disclosed, there isprovided a hollow metallic section 6 supporting the lower end of theinsulator 3 guiding and in electrical contact with the rod contact 2.Circuit lead conductors 7 and 8 are suitably connected to the contact 1and the metallic section 6, respectively. The reservoir 4 communicateswith the interior of the switch casing by means of a suitable conduitsection 9 and a. hollow insulator 10 interposed between said section andthe metallic section 6.

The conduit section 9 is provided with a valve seat 11 for the valve 5which is illustrated as operated by a. solenoid 12 for the purpose ofsimplicity. A valve particularly adapted for this purpose is disclosedand claimed in my. copending application Serial No. 451,388, filed May10, 1930, for a valve system. It is therefore believed unnecessary todescribe further the valve system other 1 than to mention that openingof the valve may be effected in any suitable manner as by manual controlof a tripping circuit by the operator, or by an overload impulseproduced by the usual current transformer.

The operating mechanism for the circuit breaker comprises in the presentinstance a piston 13 operating within a cylinder 14 and connected, as bypm and slot connection 15, to one arm of a bellcrank 16. The bellcrankis provided with a fixed pivot 17 and is connected at its other end toan insulating connecting rod 18 in turn connected as at 19 to the rodcontact 2. Reciprocal movement of the actuating piston 13 is thereforeeffective to cause engagement and disengagement of the contacts 1 and 2.

In case the gas supply is applied directly;

by means of the valve 5, to both the switch chamber and the piston 13 itwill be apparent that the time required for piston 13 to complete itsstroke and move the contact 2 to its final open position is much longerthan the time required for interruption of arcing by the high pressureblast exhausting through the nozzle contact 1. For the purpose ofeliminating the waste of gas energy at the nozzle contact I haveprovided means for shutting off the main blast within a short time andfor utilizing stored gas energy for completing the switch openingoperation. More specifically, a quantity of gas under pressure istemporarily stored or entrapped upon opening of the main valve sothatnotwithstanding closure of said valve after ad mitting a brief highpressure blast to the switch contacts, the stored gas energy iseffective to complete the opening movement of the contact actuatingpiston.

To this end the cylinder 14 is connected to the conduit section 9 at apoint beyond the main valve 5, as by a pipe 20, including a storagespace or gas accumulator 21. For the purpose of preventing reverse flowof gas through the accumulator 21, the same is provided with a suitableone-way valve as a flap valve 22. It will be understood, of course, thatthe accumulator 21 may comprise a portion of the cylinder 14 on theworking side of the piston 13.

The operation is as follows: When the main valve 5 is opened, as at thewill of the operator or in response to an abnormal circuit condition, asupply of gas at high pressure is directed from the reservoir 4 throughthe conduit section, 9 so that pressure is applied practicallysimultaneously to the switch contacts and to the actuating piston 13.The valve 22 within the accumulator 21, it will be noted, does notprevent full application of the gas pressure to the piston 13. As thecontacts 1 and 2 separate the resulting high pressure blast through thenozzle contact 1 quickly extinguishes arcing so that the main valve 5may beclosed, in so far as the interrupting blast is concerned, duringthe remainder of the circuitopening movement. Immediately upon closureof the valve 5 gas under high pressure is entrapped within theaccumulator 21 by reason of the valve 22, so that the stored energy ofthis gas continues to move the piston 13 to its limiting open circuitposition. Accordingly, the gas energy is applied in the most effectivemanner wit out unnecessary waste. The circuit breaker may be closed inany suitable manner as by mechanical means or by a pressure connection(not shown) to the opposite side of the cylinder 14. t

It should be understood that my invention is not limited to specificdetails of construction and arrangement thereof herein illus-. trated,and that changes and modifications may occur to one skilled in the artwithout departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. A gas blast circuit breaker comprising relatively movable contacts, asource of gas pressure, a valve controlling flow of gas from said sourcefor extinguishing arcing between said contacts and for causingseparation thereof, and means for completing separation of said contactsafter closure of said valve.

2. A gas blast circuit breaker comprising a source of gas pressure,relatively movable contacts, a valve controlling flow of gas from saidsource, means directing said gas flow simultaneously to operating meansfor separating said contacts and to said contacts for extinguishingarcing, and means utilizing .stored gas energy for completing separationof said contacts after closureof said valve.

3. A gas blast circuit breaker comprising relatively movable contacts, asource of gas pressure, a main valve controlling flow of gas from saidsource, a piston for causing relative movement of said contacts, openingof said valve causing application of gas pressure simultaneously to saidpiston and to said contacts so that arcing between said'contacts isextinguished upon separation thereof, and a gas accumulator disposedbetween said source and said piston arranged so that said piston ismoved to its limiting position by gas pressure subsequent to closure ofsaid valve.

4.v A gas blast circuit breaker comprising relatively movable contacts,a source of gas pressure, a piston for effecting relative movement ofsaid contacts, a main valve controlling flow of gas from said source,means directing said gas upon opening of said valve simultaneously tosaid piston and to said contacts, a gas storage spaceinterposed betweensaid piston and said main valve, and a oneway valve preventing reverseflow of gas from said storage space, said storage space beingproportioned so that gas entrapped therein after closing, of said main.valve is efiective to cause continued movement of said piston to itslimiting open circuit position.

5. A gas blast circuit breaker comprising relatively movable contactsoperating means including a piston for eifecting relative movement ofsaid contacts, a source of gas ressure, a main valve for controllingflow gas 5 from said source for a limited time corresponding to theblast required at said contacts for extinguishing of arcing, and anaccumulator provided with a valve preventing reverse flow interposedbetween said piston and said source for continuing application of gaspressure to said piston after closure of said main valve.

In1 witness whereof I have hereunto set my han WERNER UEBERMUTH.

